Child support adjustment - anyone been through this?

Just got laid off from my job and I'm looking at probably a 30% pay cut when I find something new. My ex gets child support from me and I know I need to go back to court to adjust it. Has anyone done this? Do I need a lawyer or can I do it myself? I'm worried she's gonna fight me on it but I literally cannot afford the current amount on unemployment benefits. Any advice appreciated.